RLC delivery failure resolution

Abstract

A method in a first node of a telecommunications network, in which a Radio Link Control (RLC) controller detects a failure to transmit a first RLC data Protocol Data Unit (PDU) containing all or part of a Service Data Unit (SDU) towards a second node of the telecommunications network, and notifies a Radio Access Control (RAC) controller of the failure. The RAC controller, in response to receiving a dedicated control channel (DCCH) message from the second node subsequent to the notification, instructs the RLC controller to retransmit the SDU. In response to the instruction, the RLC controller transmits a second RLC data PDU containing the SDU or a part of the SDU towards the second node. The RLC controller, in further response to the instruction, transmits a receipt of delivery to the RAC controller when reception of all parts of the SDU has been positively acknowledged by the second node.

The invention claimed is: 
     
       1. A method in a first node of a telecommunications network, the method comprising:
 in a Radio Link Control (RLC) controller of the first node:
 attempting to transmit a plurality of RLC data Protocol Data Units (PDUs), each containing a respective part of a Service Data Unit (SDU), towards a second node of the telecommunications network; 
 detecting a failure to transmit a first RLC data PDU of the plurality of RLC data PDUs; and 
 notifying a Radio Access Control (RAC) controller of the first node of the failure; 
 
 in the RAC controller of the first node:
 in response to receiving a dedicated control channel (DCCH) message from the second node subsequent to said notification, instructing the RLC controller to retransmit the SDU; 
 
 in the RLC controller of the first node:
 in response to the instruction, transmitting a second RLC data PDU containing the part of the SDU contained within the first RLC data PDU towards the second node, wherein transmitting the second RLC data PDU comprises setting a flag on the second RLC data PDU to allow retransmission of the first RLC data PDU when a count of retransmission of the first RLC data PDU is above or equal to a threshold; and 
 in further response to the instruction, transmitting a receipt of delivery to the RAC controller when reception of all parts of the SDU has been positively acknowledged by the second node. 
 
 
     
     
       2. The method according to  claim 1 , wherein transmitting the second RLC data PDU further comprises setting a sequence number (SN) of the second RLC data PDU equal to a sequence number of the first RLC data PDU. 
     
     
       3. The method according to  claim 1 , wherein the first node is a base station or an eNodeB and the second node is a user equipment (UE). 
     
     
       4. The method according to  claim 3 , wherein the SDU contains a UE reconfiguration command. 
     
     
       5. The method according to  claim 4 , wherein the SDU contains a UE handover command. 
     
     
       6. The method according to  claim 3 , wherein the DCCH message contains a measurement report. 
     
     
       7. The method according to  claim 1 , wherein the telecommunications network is:
 a Long Term Evolution (LTE) network; or 
 a 3G network. 
 
     
     
       8. An apparatus configured to operate as a first node of a telecommunications network, the apparatus comprising:
 a Radio Access Control (RAC) controller; 
 a transceiver configured to communicate with a second node of the telecommunications network; and 
 a Radio Link Control (RLC) controller configured to: attempt to transmit a plurality of RLC data Protocol Data Units (PDUs), each containing a respective part of a Service Data Unit (SDU) towards the second node of the telecommunications network, detect a failure to transmit a first RLC data PDU of the plurality of RLC data PDUs, and notify the RAC controller of the first node of the failure, 
 wherein the RAC controller is configured to, in response to reception of a dedicated control channel (DCCH) message from the second node subsequent to said notification, instruct the RLC controller to retransmit the SDU, 
 wherein the RLC controller is further configured to:
 in response to the instruction, cause the transceiver to transmit a second RLC data PDU, containing the part of the SDU contained within the first RLC data PDU, towards the second node, and wherein, to transmit the second RLC data PDU, the RLC controller is configured to cause the transceiver to set a flag on the second RLC data PDU to allow retransmission of the first RLC data PDU when a count of retransmission of the first RLC data PDU is above or equal to a threshold; and 
 in response to the instruction, transmit a receipt of delivery to the RAC controller when reception of all parts of the SDU has been positively acknowledged by the second node. 
 
 
     
     
       9. The apparatus according to  claim 8 , wherein the RLC controller is further configured to set a sequence number (SN) of the second RLC data PDU equal to an SN of the first RLC data PDU. 
     
     
       10. The apparatus according to  claim 8 , wherein the apparatus is configured to operate as a base station or an eNodeB. 
     
     
       11. The apparatus according to  claim 10 , wherein the SDU contains a user equipment (UE) reconfiguration command. 
     
     
       12. The apparatus according to  claim 11 , wherein the SDU contains a handover command. 
     
     
       13. The apparatus according to  claim 10 , wherein the DCCH message contains a measurement report. 
     
     
       14. A non-transitory computer readable storage medium that stores program code which when run on an apparatus causes a first node of a telecommunications network to perform operations comprising:
 attempting, in a Radio Link Control (RLC) controller of the first node, to transmit a plurality of RLC data Protocol Data Units (PDUs), each containing a respective part of a Service Data Unit (SDU), towards a second node of the telecommunications network; 
 detecting, in the RLC controller of the first node, a failure to transmit a first RLC data PDU of the plurality of RLC data PDUs; 
 notifying a Radio Access Control (RAC) controller of the first node of the failure; 
 instructing, in the RAC controller, for the RLC controller to retransmit the SDU, in response to receiving a dedicated control channel (DCCH) message from the second node subsequent to said notification in the RAC controller of the first node; 
 transmitting a second RLC data PDU containing the part of the SDU contained within the first RLC data PDU towards the second node in response to the instruction wherein transmitting the second RLC data PDU comprises setting a flag on the second RLC data PDU to allow retransmission of the first RLC data PDU when a count of retransmission of the first RLC data PDU is above or equal to a threshold; and 
 transmitting from the RLC controller, further in response to the instruction, a receipt of delivery to the RAC controller when reception of all parts of the SDU has been positively acknowledged by the second node. 
 
     
     
       15. The non-transitory computer readable storage medium of  claim 14 , wherein the program code which when run on the apparatus, further causes the first node to perform operations comprising transmitting the second RLC data PDU by setting a sequence number (SN) of the second RLC data PDU equal to a sequence number of the first RLC data PDU. 
     
     
       16. The non-transitory computer readable storage medium of  claim 14 , wherein the program code which, when run on the apparatus, causes the first node to perform operations where the first node is a base station or an eNodeB and the second node is a user equipment (UE). 
     
     
       17. The non-transitory computer readable storage medium of  claim 16 , wherein the program code which, when run on the apparatus, causes the first node to perform operations where the SDU contains a UE reconfiguration command. 
     
     
       18. The non-transitory computer readable storage medium of  claim 17 , wherein the program code which, when run on the apparatus, causes the first node to perform operations where the SDU contains a UE handover command. 
     
     
       19. The non-transitory computer readable storage medium of  claim 16 , wherein the program code which, when run on the apparatus, causes the first node to perform operations where the DCCH message contains a measurement report. 
     
     
       20. The non-transitory computer readable storage medium of  claim 14 , wherein the program code which, when run on the apparatus, causes the first node to perform operations in the telecommunications network that is a Long Term Evolution (LTE) network or a 3G network.